Novel organo-tin compounds

ABSTRACT

An organo-tin compound is prepared by reacting a compound having the following general formula: WHEREIN R represents an alkyl group, alkenyl group or aralkyl group having one to eighteen carbon atoms, A represents a sulfur atom and l represents a mean degree of polymerization of any number of at least 2, with a monoorgano-tin compound having the following general formula: WHEREIN R has the same meaning as defined above, SX represents a group of mercaptan residue, or a group of the following general formula:

United States Patent Sassa et al.

[451 Oct. 10, 1972 [54] NOVEL ORGANO-TIN COMPOUNDS [72] Inventors: Atsuo Sassa, Tokyo; Masuo Yukutomi, Fuchu-shi; Hirotoshi Shinkawa, Musashino-shi; Tuneo Moriya, Otsu-shi; Keisuke Homma, ltami-shi, all of Japan [73] Assignees: Kyodo Chemical Company Limited;

Primary Examiner-Tobias E. Levow Assistant Examiner-Werton F. W. Bellamy Attumeyl(arl W. Flocks I 5 7 1 ABSTRACT An organo-tin compound is prepared by reacting a compound having the following general formula:

wherein R represents an alkyl group, alkenyl group or aralkyl group having one to eighteen carbon atoms, A represents a sulfur atom and l represents a mean degree of polymerization of any number of at least 2, with a monoorgano-tin compound having the following general formula:

/(SX)m (R-Sn wherein R has the same meaning as definedabove, SX represents a group of mercaptan residue, or a group of the following general formula:

SR'COOR" [1V] (wherein R represents an alkylene group, cycloalkylene group, alkenylene group and phenylene group having one to eight carbon atoms, R represents a hydrogen atom or an alkyl group, cycloalkyl group, alkenyl group or aralkyl group), SY represents a group of said SX or a group of the following general formula:

I F l i." i (wherein R has the same meaning as defined above, G represents an oxygen atom, sulfur atom, carbon atom or a methylidyne group, w represents an integer of l to 4, x represents an integer of 0 or 1, y represents an integer of 1 to 8 and 2 represents an integer of 2 to 4) or a group of the following general formula:

(wherein R has the same meaning as defined above, E represents a group of said SX or a group of the general formula [V], q represents an integer of 1 to 3 and r represents an integer of l or 2), m and n represents integers, where m n 3, and p represents a mean degree of polymerization of any number of at least 1, or compounds having the general formula:

l-lSY [V11] wherein SY has the same meaning as defined above, by heating to a temperature of not more than 300 C., or by reacting a compound having the following general formula:

R-Sn (X) vm with compound having the general formula:

MSY [1X] MSR'COOM x wherein X represents a halogen atom, M represents an alkali metal, and SY and R have the same meanings as defined above, at a temperature of not more than 100 C., and further reacting the resulting compound having the following general formula:

wherein R, X and SY have the same meanings as defined above, and d and e represent integers of 1 or 2, with at least one of caustic alkalis and alkali metal sulfides at a temperature of not more than 100 C.

The organo-tin compound is very excellent as stabilizers for plastic owing to its non-toxicity.

,7 ,w imsN m NOVEL ORGANO-TIN COMPOUNDS This invention relates to novel and useful organo-tin compounds, and more particularly to organo-tin compounds obtained by reacting at least one of compounds having the following general formula:

wherein R represents an alkyl group, alkenyl group or aralkyl group having one to 18 carbon atoms, these groups being able to contain substituent groups, A represents a sulfur atom and 1 represents a mean degree of polymerization of any number of at least 2, with at least one compound selected from the group consisting of monoorgano-tin compounds having the following general formula:

in (M4 57 P wherein R has the same meaning as defined above, SX represents a group of mercaptan residue, or a group of the following general formula:

(wherein R has the same meaning as defined above, G represents an oxygen atom, sulfur atom, carbon atom or a methylidyne group, w represents an integer of l to 4, x represents an integer of or I, y represents an integer of l to 8 and 2 represents an integer of 2 to 4) or a group of the following general formula:

(wherein R has the same meaning as defined above, E represents a group of said SX or a group of the general formula [V], q represents an integer of l to 3 and r represents an integer of 1 or 2), m and n represent integers, where m n 3, and p represents a mean degree of polymerization of any number of at least 1,

and compounds having the general formula:

HSY (VII) wherein SY has the same meaning as defined above, in the presence or absence of a solvent by heating to a temperature of not more than 300C., or by reacting a compound having the following general formula:

R-Sn (X) (VIII) with a compound having the following generalformula:

MSY (1x) or MSRCOOM (X) wherein X represents a halogen atom, M represents an alkali metal, and SY and R have the same meanings as defined above, at a temperature of not more than C, and further reacting the resulting compound having the following general formula:

wherein R, X and SY have the same meanings as defined above, and d and e represent integers of l or 2, with at least one of caustic alkalis and alkali metal sulfides at a temperature of not more than 100C.

Heretofore, vinyl chloride resins, which will be hereinafter referred to as PVC, have been widely used on account of their excellent physical properties and low cost, but their heat molding processing (for example, extrusion processing, injection molding processing, calender processing, etc.) is not an easy and simple technique owing to the poor heat stability of the resins. Particularly in molding processing of a rigid or semirigid polyvinyl chloride resin into sheets, selection of the kind and amount of heat stabilizers is a very important technique.

The now commercially available heat stabilizers can be classified principally into inorganic salts, metallic soaps, and dialkyl tin compounds, and the respective stabilizers are subjected to their proper services according to the use and requirement of the end product. However, all of these stabilizers are not so satisfactory for the production of the sheets of a rigid or semi-rigid polyvinyl chloride resin, which will be referred to as rigid PVC or semi-rigid PVC, and which have been recently in a great demand. In producing sheets of rigid PVC or semi-rigid PVC by calendering, not only the heat stability effect is a property required for the heat stabilizer, but also the adhesion of the sheets to calender rolls, presence of permeation of the heat stabilizer to the surface of the rolls at the kneading operation, which is called plate-out or change in appearance of the sheets due to the addition of the heat stabilizer (for example, luster, transparency, presence of foams) is an important criterion for the selection.

Further, it is also necessary to prevent deterioration of physical properties due to the addition of the stabilizer. In this sense, it is necessary to select such a stabilizer that is effective even in a small amount. When the sheets are used as a wrapping material for food or medicine, the presence of toxicity or smells must be carefully investigated. For example, the stabilizers of dibutyl-tin maleates or dibutyl-tin monoalkyl maleates, which are most widely used in the extrusion molding or injection molding, have a large heat stability effect among the commercially available heat stabilizers, and have a good compatibility with PVC. Thus, sheets having a good appearance can be produced therefrom by extrusion processing or press processing, but their adhesion to rolls is considerable in calender processing and thus it is necessary to add a large amount of a lubricant or a releasing agent to the resin. This will impair the appearance of the sheets.

Furthermore, the commercially available stabilizer has'a toxic problem, and their addition is not permitted in the most cases when the sheets are used as a wrapping material for food or medicine.

The stabilizers of metal soaps have no adhesion to rolls as seen in the case of the dialkyl tin compound, almost at all, but have a poor heat stability effect. When an increased amount of the stabilizer is added to the resin, for example,.more than 1.5 PHR, there is such a drawback that the transparencyand luster of the sheets are suddenly lost.

The Cd Ba composite stabilizer has a high toxicity and cannot be applied to the sheets for wrapping the food or medicine.

As to these stabilizers, it is added that the deterioration of the physical properties due to theaddition of these stabilizers is remarkable. For example, the stabilizers of dialkyl tin compounds, which are necessary to add in a relatively large amount to obtain a heat stability effect necessary for the processing, lower the heat softening point of a composition and restrict a practical service temperature range. The stabilizers of metal soaps have a poor compatibility with PVC cause a permeation of the stabilizers to the surfaces of the sheets after the processing to sheets, and impair a sliding between'the sheets, resulting in lowering the working efficiency in the processing to sheets.

In the industry of producing sheets of rigid PVC or semi-rigid PVC by calendering, a finding of an efiective heat stabilizer has been desired owing to said situation.

The present inventors found, as a result of researches made for a long period of time, that monobutylthiostannoic acid andthe polymonobutylthiostannoic acid disclosed in Japanese Patent Publication No. 6137/60 had the most excellent effect among the wellknown stabilizers, but had no commercial value,.

because it was found that any of these monobutylthiostannoic acid and polymonobutylthiostannoic acid generated a strong hydrogen sulfide smell during the production as well as the processing of the sheets, and the metal constituting an apparatus was corroded when used for a long period of time.

On the other hand, the present inventors have found that the present compounds are effective for producing a PVC composition,particularly for producing sheets of rigid PVC or semi-rigid PVC by calender rolls and can overcome the heretofore encountered problems.

By using the stabilizer of the present invention even in a small amount, heat stability of the PVC sheets can be obtained, and the non-toxicity of the present stabilizer is also a great feature of the present invention. The present stabilizer can be added, alone or in admixture of at least two kinds of the present stabilizers, to PVC.

Mole ratio of reactants in producing the present compounds can be freely changed. That is to say, on presuming [Ra-Sn (A), of the organo-tin compound represented by the general formula [I] or [II] as a unit and calculating it as one mole, the mole ratio of mercaptan, a mercapto acid and/or its ester alone or in admixture as a reactant on one hand-to the organo-tin compound as another reactant on the other hand can be freely changed between 1 and 0.l mole. Further, the amount of a compound represented by said general formula [I] or [II] aloneor in admixture as a reactant on the general formula [XI] by reacting a compound represented by the general formula [VIII], that is, RSn (X) with a compound represented by the general formula [IX], that is, MSY, or by the general formula [X], that is, MSR'COOM, the mole ratio of a reactant represented by the general formula [IX] or [X] to another reactant represented by the general formula [VIII] can be freely changed, so long'as the ratio can permit stoichiometrically at least one atom of X to be retained in the product [XI], asshown in the general formula [XI]. The reaction temperature is C. or below, preferably l0 to 50C. In reacting the thus obtained compound represented by the general formula [XI] with a caustic alkali and/or an alkali metal sulfide, the amount of the caustic alkali and/or the alkali metal sulfide should be only more than the necessary amount for allowing one atom of X to be replaced with oxygen or sulfur. The reaction temperature is 100C or below, preferably -l0 to 50C.

Specific examples of said R are such groups as methyl, ethyl, butyl, isobutyl, octyl, 2-.ethylhexyl, octadecyl, aryl, benzyl, phenylethyl, etc.

Examples of mercaptans, mercapto acids and/o their esters are such mercaptans as octylmercaptan, laurylmercaptan, benzylmercaptan, thiophenol, nonylthiophenol, etc., such mercapto acids as thiogylcolic acid, thiopropionic acid, thiolactic acid, thiosalicylic acid, 2-mercapto-lauric acid, etc. and esters of these mercapto acids with such monohydric or-polyhydric alcohols as butyl alcohol, octyl alcohol, Z-ethylhexyl alcohol, decyl alcohol, octadecyl alcohol, ethylene glycol, propylene glycol, pentaerythritol, benzyl alcohol, phenethyl alcohol, cinnamyl alcohol, etc.

Likewise, specific examples of SX are groups of such alkylmercaptan residues as octylmercaptan residue, laurylmercaptan residue, etc., or groups of ester residues of alkyl, alkenyl, aralkyl, cycloalkyl, etc. of

thioglycolic acid, thiopropionic acid, mercaptobenzoic acid, etc., for example, butyl thioglycolate, octyl thioglycolate, cyclohexyl thioglycolate, allyl thioglycolate, cinnamyl thioglycolate, benzyl thioglycolate, octyl thiopropionate, etc.

Specific examples of SY are the same groups as SX or groups of dihydric to'tetrahydric alcohol ester residues of thioglycolic acid, thiopropionic acid, mercaptobenzoic acid, etc., for example, ethylene glycol ester, tripropylene glycol ester, glycerine I ester, neopentaerythritol ester, etc. of thioglycolic acid, or thiopropionic acid, or groups of residues of monoorgano-tin compounds of thioglycolic acid. or thiopropionic acid as represented by the general formula [VI]. I

The thus obtained organo-tin compounds of the present invention are very excellent as stabilizers for plastic owing to their non-toxicity.

The selvents used in the present invention include organic solvents having a boiling point of 300C. or lower, such as straight or branched, saturated or unsaturated hydrocarbons, aromatic hydrocarbons, heterocyclic hydrocarbons, alcohols, ester, ketones and these compounds substituted by a halogen or halogens.

The caustic alkalis used in the present invention include hydroxides of alkali metals, such as Na, K, etc., and the alkali metal sulfide used in the present invention include sulfides and hydrosulfides of alkali metals, such as Na, K, etc.

The present invention will be now explained in detail with reference to examples, but will not be limited to these examples. In the Examples, all parts and percentages used are by weight.

EXAMPLE I When 44.7 g. of powdered thiobis (monobutyl-tin sulfide) [(Bu-Sn-S) S] was reacted by heating, with 40.8 g. of 2-ethylhexyl thioglycolate (HSCH COO iso- Oct) in benzene under reflux, reaction proceeded, generating hydrogen sulfide gas. When the generation of hydrogen sulfide was stopped, the benzene was distilled off under a reduced pressure, whereby a colorless, transparent liquid of a low viscosity was obtained. The thus obtained product was a compound having the following structural formula and its tin content was 28.7 percent, which was in good accordance with the theoretical value (28.8 percent):

%s Bu-Sn s-cmooo iso-0ct Note: In the specification 2-ethylhexyl group and butyl group are referred to as iso-Oct and Bu, respectively.

EXAMPLE 2 When 44.7 g. of powdered thiobis (monobutyl-tin sulfide) [(Bu'Sn'S) S] was reacted, by heating, with 25.4 g. of diethylene glycol bisthioglycolate, (HS-CH,C 00 CH, CH, OCH; CH, OOC CH SH) in toluene under reflux, reaction proceeded, generating hydrogen sulfide gas. When the generation of hydrogen sulfide was stopped, tobuene was distilled off under a reduced pressure, whereby a colorless, transparent liquid was obtained. The thus obtained product was a compound having the following structural formula, and its tin content was 35.6 percent, which was in good accordance with the theoretical value (35.5 percent).

S Bu-Sn S CHzC O 0 CHZ'CHZ O S CHrC O O GHs-CH: Bu'Su EXAMPLE 3 When 89.5 g. of his (monobutyl-tin sulfide) oxide [(Bu-SnS), 0] was reacted, by heating, with 43.3 g. of

6 pentaerythritol tetrakisthioglycolate [C(CH,'OOC CPL-8H),] in toluene under reflux, reaction proceeded, generating water. When the generation of water was stopped, toluene w as distilled ofi under a reduced pressure, whereby a colorless, transparent, viscous liquid was obtained. The thus obtained product was a compound having the following structural formula, and its tin content was 37.5 percent which was in good accordance with the theoretical value (37.7 percent):

S CHa-CO 0 CE: /CH:0O O-CHaS- n-Bu When 52.8 g. of thiobis(octyl-tin sulfide) [(Oct-Sn' S),; S] together with 40.4 g. of laurylmercaptan was stirred in the absence of a solvent by heating to C., reaction proceeded, generating hydrogen sulfide gas. When the reaction was continued by heating until the generation of hydrogen sulfide had beenstopped, a'

slightly yellowish, transparent liquid was obtained. The thus obtained product had the following structural formula and its tin content was 25.6 percent, which was in good accordance with the theoretical value (25.5 percent) Note: In the specification, an N octyl group is referred to as Oct.

EXAMPLE 5 EXAMPLE 6 20.9 g. of monobutylstannoic acid Bu sn and 61.2 g. of Z-ethylhexylthioglycolate were subjected to dehydration reaction in benzene under reflux by heating. After the completion of the dehydration reaction, 44.7 g. of powdered thiobis (monobutyl-tin sulfide) was added further thereto, and reaction was carried out by heating under reflux for 1 hour. The, by

distilling off benzene under a reduced pressure, 75.5 g. of a slightly-yellowish liquid was obtained. The thus obtained product could be presumed as a mixture of:

S -CH:-C 0 O iso-Oct);

Bu- S n Bu-Sn S and' B Bu-Bn a compound having the following structural formula:

Bu-Sn [Bu-Sn(S CHzCOO iso-Octm- S Bu-Sn The Sn content and S content thereof were 29.0 percent and 15.7 percent, respectively, which were in good accordance with the theoretical values (Sn 29.3 S 15.9 11). V

EXAMPLE 7 41.8 g. of monobutylstannoic acid SCHTOOOCHTCEi' 0 Bu- 8 n-SCHz-COOCEhCfiz S SOIL-0000112052 Bl].- SQ

SCHz-COOCIL-CH: Bu- Sn Bu- Sll-SCHz-COOCHTCQZ 0 SCHz-COOCHz-CHz song-000mm SCHz-COO(C 3)2 l O Bu-Sn The Sn content and S content of these compoundswere 30.3 percent and. 18.3 percent respectively, and were in good accordance with the theoretical values (Sn=30.6%,S= 18.5%).

v EXAMPLE 8 20.9 g. of monobutylstannoic acid 0 Bu- Sn 20.2 g. of laurylmercaptan and 34.8 g. of cyclohexylthioglycolate were subjected to dehydration reaction in benzene under reflux by heating, and after the completion of the dehydration reaction, 44.7 g. of thiobis (monobutyl-tin sulfide) was further added thereto. The reaction was carried out by heating under reflux for 1 hour. Then, by distilling ofl benzene under a reduced pressure, 1 17 g. of a slightly yellowish liquid was obtained. The thus obtained product was found to be a mixture of:

sbmcoo Bu-Sn and or a compound having the following structural formula:

Bu-Sn SCmHu Bu- Sn Bu-Sn (S-CHi-COO Note: In the specification, a cyclohexyl group is referred to as EXAMPLE 9 20.9 g. of mobobutylstannoic acid, 27.4 g. of dodecyl thiopropionate, and 18.2 g. of benzyl thioglycolate were subjected to dehydration reaction in benzene under reflux by heating, and after the completion of the dehydration reaction, 44.7 g. of thiobis (monobutyl-tin sulfide) was further added thereto, and the reaction was carried out by heating under reflux for 1 hour. Then, by distilling off benzene under a reduced pressure, 62.5 g. of a slightly yellowish liquid was obtained. The thus obtained product was found to be a mixture of:

somcmoooomnu Bu-SuSCHzCO war-G SCHz-COOCHQ and or a compound having the following structural formula:

SCHzCH2COOC12H25 Bu- Sn /s (somcoo CHZQ) Bu-Sn EXAMPLE 10 52.9 g. of monooctylstannoic acid and 27.6 g. of thioglycolic acid were subjected to dehydration reaction in benzene under reflux by heating, and after the completion of the reaction, 44.7 g. of thiobis (monobutyl-tin sulfide) was further added thereto, and the reaction was further carried out by heating under reflux for 1 hour. Then, by distilling off benzene under a reduced pressure, 73 g. of a slightly yellowish, viscous liquid was obtained. The thus obtained liquid was solidified in an amorphous state while kept stored.

The thus obtained product could be presumed as a compound of the following type, and its Sn content and S content were 40.1 percent and 16.0 percent, respectively and were in good accordance with the theoretical values (Sn= 40.3 S 16.3

EXAMPLE 11 24.3 g. of monobenzylstannoic acid (Que-sf by heating, and after the completion of the reaction, 40.5 g. of powdered thiobis (monoallyl-tin sulfide) [(CH, CH CH, SnS),S] was further added thereto and the reaction was further carried out by heating under reflux for 1 hour. Then, by distilling off benzene under a reduced pressure, 122.4 g. of a slightly yellowish liquid was obtained. The thus obtained product could be presumed to be a mixture of:

ame o 0 -001;), G

and

SCHQC 0O 'iso-0ct CHz=CH' CH2 SD.

or a. compound of the following type:

(@omsmsomc o 0 -iso-Oct)a) its Sn content and S content were 29.0 percent and 15.5 percent respectively and were in good accordance with the theoretical values (Sn 29.1 S 15.7

EXAMPLE 12 128.3 g. of monolaurylstannoic acid O C uHuSn and 129.6 g. of pentaerythaitol'tetrakis-thioglycolate HSCHHCOOCHZ CHzOOCCHzSH HSCHzCOOC 2 CHzOOCCHzSH were subjected to dehydration reaction in benzene under reflux by heating, and after the completion of the reaction, 44.7 g. of thiobis (monobutyltin sulfide) was further added thereto, and the reaction was further carried out by heating under reflux for 2 hours. Then, by distilling off benzene under a reduced pressure, 288 g. of a slightly yellowish, amorphous solid was obtained. The thus obtained product could be presumed as a compound having the following structural formula, and its Sn content and S content were 24.6 percent and 16.5 percent and were in good accordance with the theoretical va1ues(Sn 24.7 S 16.7

CHzOOC CHzS Sn-Lau CHzCOOCHgS Bu-Sn SCHz-COOCE: /CH:COOCH2S Sn-Lau SCHz-COOC z CHzCOOCHzS Lau-Sn EXAMPLE 13 and 168 g. of, ethylene glycol thioglycolate (HS-CH; COOCH,CH,OOC-CH,'SH) were subjected to dehydration reaction in benzene under reflux by heating, and after the completion of the dehydration reaction, 22.4 g. of monobutyl-tin sulfide polymer {[Bu-Sn (S), was furtheradded thereto, and thereaction was carried out by'heating under reflux for 1 hour. Then, by distilling off benzene under a reduced pressure, 388.5 g. of a slightly yellowish liquid was obtained. The thus obtained product could be presumed as a compound having the following structural formula and its Sn content and S content were 27.5 percent and 16.5 percent, respectively.

EXAMPLE 14 20 g. of an aqueous 20 percent caustic soda solution was added to 400 ml. of a methanol solution containing 20.4 g. of 2-ethylhexyl ester of thioglycolic acid while cooling the methanol solution with water, and then an aqueous methanol solution containing 28.2 g. of monobutyl-tin trichloride was added thereto dropwise while further cooling and keeping the solution at a temperature of to C. After the completion of the dropwise addition, .the reaction was continued with stirring at 5 to C. for 30 minutes, and then the solution was again cooled to 0 to 5C. An aqueous 10 percent solution containing 8 g. of Na,S was further added thereto dropwise and subjected to reaction. Then, 50 ml. of toluene wasadded thereto at a temperature of l0 to 30C. and further 100 ml. of water was added thereto, whereby the reaction solution was separated into two layers. After the separation of the layers, by distilling off toluene from the toluene layer under a reduced 65 1 was obtained. lts tin content was 28.4 percent.

EXAMPLE 15 The respective stabilizers as shown in Table l were added to commercially available PVC of 1 E 800 produced by a suspension polymerization process, and after kneading the mixture by 6-inch rolls and molding it to sheets, the sheets were left at 180C. in a Geertype aging tester to observe the incipient coloring and the time till blackening at an interval of 5 minutes. As necessary lubricants for the kneading, -1 .0 part of stearic acid and 0.2 part of low molecular weight polyethylene were added thereto.

TABLE 1 Blend Kind of Stabilizer amount incipient blacken- No. added coloring ing time (mm.)

1 Present product, 0.5 hardly 50 Type [lX]"* yellowish 2 Present product, 5 5

yp l l' 3 Present product, I 45 Type nanoa 4 Present product,

7 Type uv oaaau 5 di-octyl tin maleate slightly 40 (commercially avail) yellowish 6 di-butyl tin maleate (commercially avail) 7 di-butyltin 45 mercaptide 1 (commercially avail 8 Liquid Cd-Ba 10 consider- 30 Composite ably stabilizer yellowish (commercially avail) 9 Powdered Cd-Ba slightly 35 Composite yellowish stabilizer (commercially avail) l0 Polymonobutylthio- 0.5 slightly stannoic acid dark 5 5 yellow 1 l Polymonobutylconsider 25 stannoic acid ably dark yellow 12 Ca-Zn organic com- [.0 slightly 20 polite stabilizer yellow 13 Di-octyl tinv 0.5 slightly 45 mercaptide yellow (commercially avail) l4 Co-condensate of Consider- 30 butylstannoic acod abl'y dark and polybutylyellow stannoic acid(l 2).

Note: Number of parts to parts of PVC resin iso-O ct =2-ethylhexyl group Bu =buty1 group S 011 O O(CH2)1O (CHmO O CHzS l shows the degree of polymerization of at least 1.

*****a mixture of s onto 0 0 GHQ Each blend of said Example was tried to make a sheet therefrom by means of an inversed L-type calender rolls of 14-inch diameter. As a result, blends Nos. 5, 6, 7, 8 and 13 containing commercially available stabilizers of tin system adhered to the calender rolls immediately after the blends were supplied to the calender rolls, and could not be made in sheets.

Further, in order to prevent the sheets from adhesion to the calender rolls, the amount of thelubricant was increased (1.5 parts of stearic acid and 0.7 part of low molecular weight polyethylene), but the adhesion took place about minutes after the supply of the blends, and the resulting sheets were white turbid owing to the increased amount of the lubricant.

From blends Nos. 1, 2, 3 and 4 containing the stabilizers of the present invention as shown in Table 1, very excellent calender sheets could be continuously made.

Sheets could be made from blends Nos. 8 and 9, but the resulting sheets, were considerably yellowish (particularly blend No. 8) and were poor also in the transparency.

1n the sheet prepared from blend No. 9 of Table 1, dispersion of fine foams was observed. 1

Blend No. 10 of Table 1 gave a good calender processability next to the blends containing the present stabilizer and a sheet having excellent appearance, but

scattering of small fisheyelike defects was observed on the resulting sheet. Considerable hydrogen sulfide smalls were generated during the processing and it was difficult to carry out a continuous, long run operation.

Likewise, blends Nos. ll, 12 and l4'of Table 1 underwent thermal decomposition at a resin holding part between rolls, which was called bang, during the continuous operation, and contamination of the sheet with blackened matters was observed.

EXAMPLE 17 Several kinds of copolymers consisting principally of vinyl chloride, and mixtures of the so-called polymerreinforcing agent, for example, commercially available acrylonitrile-butadiene-styrene copolymer (which is called ABS) or rnethylmethacrylate-butadienestyrene copolymer (which is called MBS) with a vinyl chloride polymer were subjected to heat resistance test (temperature 170C.) by means of a Geer aging tester to investigate the incipient coloring and blackening time.

The results are given in Table 2. As the stabilizers 0.5 part of Type [IX] of Table l and 1.0 part of the commercially available Cd-Ba composite stabilizer for the comparison sake were used. The lubricant of Example 15 was used in the same manner as in Example 15.

TABLE 2 Other Blend Resin resin stabilizer incipient blacken- No. Composicontent coloring ing time tion (min.)

1 V-VAC VAC 5% Present Made 55 .copolymer stabilizer hardly ('p'= 760) type [IX] yellowish 2 u u 10% l. u 3 L 5% Cd-Ba 35 composite Y stabilizer 4 il l it 5 Mixture VAC 5% Present Made 60 of PVC stabilizer hardly (5 760) Type [1X] yellowish and M88 6 ll u u ll 7 30% u 8 5% Cd-Ba Slightly 40 composite yellowish stabilizer 9 15% Brown 30 10 30% Dark 25 brown EXAMPLE l8 Blend Nos. 2 and 9 of Table 2 were selected and sheets were made therefrom in the same manner as in Example 16. The thus obtained sheets had an excellent gloss and transparency and could be used effectively as wrapping material. Further, it was found that the calender operation was effected very easily, and no hydrogen sulfide smell or no scattering of fisheye-like defects as in the use of polybutyl-thiostannoic acid were observed at all.

EXAMPLE 19 One of the features of the heat stabilizers of the present invention is that the present stabilizer is effective even in a small amount, as compared with the wellknown stabilizers. As specific examples, the cases of sheetpreparation by calender are given in Table 3. The

present stabilizer, Type [IX] of Table l and a commercially-available, liquid Cd-Ba composite stabilizer, for the comparison sake were used. The'same calender rolls and the, compositions except the stabilizers were used as in Example 16.

TABLE 3 Degree of Kind of Amount of incipient Calender stabilizer nabilizer coloring of procembility sheet Present 0.02 Made strongly Thermal decomstabilizer yellowish position was Type [lX] observed during the calendering 0.03 Good n OJ 0.7 No difference almost at all L2 Slight plate-out was observed on calender rolls Liquid 1.0 Made strongly Good, but the Cd-Ba yellowish sheet was made m is yL ts 'iiibiiiii? turbid l.5 Made slightly Good, but the yellowish sheet was made strongly white turbid We claim:

1. An organo-tin compound obtained by reacting at least one of the compounds having the formula:

SY) I: (III) wherein R has the same meaning as defined above, SX is a merapto residue or a group of the formula SR COOR" 11V).

wherein R is alkylene, cycloalkyle'ne, alkenylene or phenylene of one to eight carbon atoms, these groups being able to contain a C, C, alkyl group, and R" is hydrogen, alkyl, cycloalkyl, alkenyl or aralkyl, these groups being able to contain chlorine or a C, C, alltyl group,

SY is a group of SX or a group of the formula:

I I oocn s] wherein R has the same meaning as defined above; G is oxygen, sulfur, carbon or methylidyne; w is an integer of l 4; x is an integer ofO or I; y is an in- I teger of l 8; and z is an integer of2 -4, or a group of the formula 0 o c we E"!- (VI) wherein R and R have the same meanings as defined above, E is a group of said SX or a group of the formula [V], q is an integer of l 3 and r is an integer of 1 2,

m and n are integers such that m n 3, and p represents a mean degree of polymerization ofat least 2; A process for producing an organo-tin compound which comprises reacting at least one of the compounds having the following formula:

5 R-Bn SH (I) wherein R is an alltyl, alkenyl or aralkyl of one to 18 carbon atoms, these groups being able to contain sub,- stituent groups, and 1 represents a mean degreeof polymerization of at least2,

with at least one compound selected from the group consisting of mono-organo-tin compounds having the formula /(sx)m I Rn-Bn J sit (in) wherein R has the same meaning as defined above, SX is a merapto residue or a group of the formula where R has the same meaning as defined above; G is oxygen, sulfur, carbon or methylidyne; w is an integer of 1 4; x is an integer of 0 or l; y is an integer of 1 8; and z is an integer of 2 4,

or a group of the formula wherein R and R have the same meanings as defined above, E is a group of said SX or a group of the formula [V], q is an integer of l 3 and r is an integer of l 2, m and n are integers such that m n 3, and p represents a mean degree of polymerization of at least 1.

t i i UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,697,566 Dated October 10, 1 972 Inventor(s) ATSUO SASSA,: MASUO YUKUTOMI,: HIROTOSHI SHINKAWA,Z

TUNEO MORIYA anCT KEISUKE HOMMA It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 8 and 9, Sumitomo Bakelite Company Limited, Tokyo, Japan Signed and sealed this 24th day of April 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents can! PO 1050 (10 69) uscoMM-Dc 60376-1 69 U.S. GOVERNMENT PRINTING OFFICE: I969 0366334 I v 

2. A process for producing an organo-tin compound which comprises reacting at least one of the compounds having the following formula: wherein R is an alkyl, alkenyl or aralkyl of one to 18 carbon atoms, these groups being able to contain substituent groups, and l represents a mean degree of polymerization of at least 2, with at least one compound selected from the group consisting of mono-organo-tin compounds having the formula wherein R has the same meaning as defined above, SX is a merapto residue or a group of the formula -SR'' COOR'''' (IV) wherein R'' is alkylene, cycloalkylene, alkenylene or phenylene of one to 8 carbon atoms, these groups being able to contain chlorine or a C1 - C9 alkyl group, and R'''' is hydrogen, alkyl, cycloalkyl, alkenyl or aralkyl, these groups being able to contain chlorine or a C1 - C9 alkyl group, SY is a group of SX or a group of the formula: ((G)x-(R'')w OOCR''S )Z where R'' has the same meaning as defined above; G is oxygen, sulfur, carbon or methylidyne; w is an integer of 1 - 4; x is an integer of 0 or 1; y is an integer of 1 - 8; and z is an integer of 2 - 4, or a group of the formula wherein R and R'' have the same meanings as defined above, E is a group of said SX or a group of the formula (V), q is an integer of 1 - 3 and r is an integer of 1 - 2, m and n are integers such that m + n 3, and p represents a mean degree of polymerization of at least
 1. 